With the development of the modern technology and advancements in biotechnology, GNSS technology, and information technology we see a wide application of modem technology in agriculture, leading to the emergence of precision agriculture. As a core carrier of the precision agriculture, the agricultural machinery automatic driving system is significant for various agricultural tasks including farming, sowing, fertilization, irrigation, vegetation protection, harvesting, etc.
In order to improve the accuracy of the agricultural vehicle automatic driving system, it is necessary to measure the navigation accuracies of agricultural vehicle co-ordinates, the heading angle and the attitude angle, therefore the measurement values should be as accurate as possible. In particular, when the agricultural vehicles equipped with GNSS receivers are moving in the fields, the GNSS receiving antenna is tilted due to the vibrations of the vehicle body resulting from an uneven force exerted on the tires from the soil. As a result, the GNSS antenna does not coincide with the centroid of the vehicle body, so accurate attitude angles and heading angles of the vehicle body are necessary.
At present, the method of measuring GNSS attitudes with multiple antennas is often used. However, this method has the disadvantages of high cost, delay of antenna reception, poor real-time performance and difficulty in installation. As to the inertial navigation INS used in the land navigation system for attitude determination, because of high cost etc., it is not applicable to the attitude determination of the agricultural vehicle.